I won't deny that the Ancients most assuredly held fundamentally different values toward life and the lives of their creations. However, while they may be alien in some ways, I do not think they are so disconnected from normal humanity that their views cannot be understood realistically, or aligned with our own. I would argue the Ancients have more similarities with us than they do differences, and those differences can be rationally understood. Death in and of itself for example was not a terrible thing for them, so much so that the term 'death' was scarcely used. This was because their lives spanned a nigh-on eternity, and they could live as much as they pleased. They also understood the world's cycle of rebirth, and that death is not the end of things. As such, they were happily willing to offer new insight as the person that they would become, when their duty reached an end. However, what was an unprecedented and awful thing to even consider for them, was the idea of a death that was not on the person's own terms. "Such tragedy, yet no catharsis." In that sense, life is absolutely important, as well as the individual contributions of the person living it. Venat putting the entire world in a state where no one can choose their own fate in the end is the worst thing imaginable for the Ancients.
That was also why being sacrificed to Zodiark was absolutely an act of altruism, and why Emet-selch, a fellow Ancient, frames it as such in Shadowbringers. Because they are voluntarily removing themselves from the lifestream to feed Zodiark's strength; to save everyone. They are condemning themselves to what they perceive to be an awful fate for the sake of those they love. It's not that they have less of a value for life, it's that their understanding of life is different.
Hermes sadness regarding the fates of the Ancient's creations was reasonable, but in the end, he refused to turn this sadness into something that would make for constructive change in his society, and it warped into essentially 'how dare people be happy in a society where I am unhappy.' And we know this change is possible, we sow some of the seeds of it ourselves. Ancients are introduced to the idea of valuing past creations more deeply, and are confronted with the notion of such lives they create not being simple aether, and like them, having the ability to host a soul. That capacity for change was there, as both Emet-selch and Hythlodaeus, staunch representatives of the Ancient's fundamental way of living, were able to see things from that perspective eventually. It's just that neither Hermes nor Venat were willing to put in the effort to enact that change themselves. In my view, they gave up on their people, where we wouldn't have, especially by not informing the Ancients that there was ever an 'underlying issue' in the first place.